Synthesis and characterization of alkyl substituted poly(thiophene-2,5-diylvinylenes)

A new synthetic route for the preparation of poly(thiophene-2,5-diylvinylene)s consisting of the C-C coupling reaction of alkyl-substituted 2,5-diiodothiophene and E-1,2-bis(tri-n-butylstannyl)ethylene catalysed by palladium complexes is described. The resulting polymers are soluble. These materials have been extensively characterized by Fourier-transform infra-red and C-13 nuclear magnetic resonance spectroscopy. The optical properties have been examined. The polymers are deep blue in the neutral state and transparent in the doped state. The solid-state structure of these materials will be discussed according to X-ray diffraction data.